package com.sixuerain.heartkey.prayer.db;

import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
import android.database.sqlite.SQLiteException;
import android.database.sqlite.SQLiteOpenHelper;

import com.sixuerain.heartkey.app.base.JLog;
import com.sixuerain.heartkey.prayer.db.table.HomeworkTable;
import com.sixuerain.heartkey.prayer.db.table.LectionTable;
import com.sixuerain.heartkey.prayer.db.table.ReaderRecordTable;
import com.sixuerain.heartkey.prayer.db.table.UserTable;


/**
 * SQLiteOpenHelper
 * 
 */
public  class DatabaseHelper extends SQLiteOpenHelper {
	private static final String TAG = "DatabaseHelper";
	
	private static final String DB_PATH = "/data/data/heartkey/databases/";
	private static final String DATABASE_NAME = "HeartKey_db";
	private static final int DATABASE_VERSION = 1;
	private static DatabaseHelper instance = null;
	private Context mContext;
	private SQLiteDatabase myDataBase;
	
	

	public DatabaseHelper(Context context) {
		super(context, DATABASE_NAME, null, DATABASE_VERSION);
		this.mContext = context;
	}
	
	public DatabaseHelper(Context context,String dbName) {
		super(context,dbName,null,DATABASE_VERSION);
		this.mContext = context;
	}

	public DatabaseHelper(Context context, String name,
			CursorFactory factory, int version) {
		super(context, name, factory, version);
		this.mContext = context;
	}
	
	

	public static synchronized DatabaseHelper getInstance(Context context) {
		if (null == instance) {
			instance =  new DatabaseHelper(context);
		}
		return instance;
	}
	
	@Override
	public void onCreate(SQLiteDatabase db) {
		JLog.d(TAG, "Create Database.");
		db.execSQL(LectionTable.CREATE_TABLE);
		db.execSQL(HomeworkTable.CREATE_TABLE);
		db.execSQL(UserTable.CREATE_TABLE);
		db.execSQL(ReaderRecordTable.CREATE_TABLE);
		
	}

	@Override
	public synchronized void close() {
		JLog.d(TAG, "Close Database.");
		super.close();
	}

	@Override
	public void onOpen(SQLiteDatabase db) {
		JLog.d(TAG, "Open Database.");
		super.onOpen(db);
	}

	@Override
	public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
		JLog.d(TAG, "Upgrade Database.");
		dropAllTables(db);
		onCreate(db);
	}

	private void dropAllTables(SQLiteDatabase db) {
	}
	
	
//	
//    public void openDataBase() throws SQLException{
//    	 
//    	//Open the database
//        String myPath = DB_PATH + DB_NAME;
//    	myDataBase = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);
// 
//    }
// 
//    @Override
//	public synchronized void close() {
// 
//    	    if(myDataBase != null)
//    		    myDataBase.close();
// 
//    	    super.close();
// 
//	}
// 
	
	 /**
     * Copies your database from your local assets-folder to the just created empty database in the
     * system folder, from where it can be accessed and handled.
     * This is done by transfering bytestream.
     * */
    private void copyDataBase() throws IOException{
 
    	//Open your local db as the input stream
    	InputStream myInput = mContext.getAssets().open(DATABASE_NAME);
 
    	// Path to the just created empty db
    	String outFileName = DB_PATH + DATABASE_NAME;
 
    	//Open the empty db as the output stream
    	OutputStream myOutput = new FileOutputStream(outFileName);
 
    	//transfer bytes from the inputfile to the outputfile
    	byte[] buffer = new byte[1024];
    	int length;
    	while ((length = myInput.read(buffer))>0){
    		myOutput.write(buffer, 0, length);
    	}
 
    	//Close the streams
    	myOutput.flush();
    	myOutput.close();
    	myInput.close();
 
    }
	
	/**
     * Creates a empty database on the system and rewrites it with your own database.
     * */
    public void createDataBase() throws IOException{
 
    	boolean dbExist = checkDataBase();
 
    	if(dbExist){
    		//do nothing - database already exist
    	}else{
 
    		//By calling this method and empty database will be created into the default system path
               //of your application so we are gonna be able to overwrite that database with our database.
        	this.getReadableDatabase();
 
        	try {
 
    			copyDataBase();
 
    		} catch (IOException e) {
 
        		throw new Error("Error copying database");
 
        	}
    	}
 
    }
	
	  /**
     * Check if the database already exist to avoid re-copying the file each time you open the application.
     * @return true if it exists, false if it doesn't
     */
    private boolean checkDataBase(){
 
    	SQLiteDatabase checkDB = null;
 
    	try{
    		String myPath = DB_PATH + DATABASE_NAME;
    		checkDB = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);
 
    	}catch(SQLiteException e){
 
    		//database does't exist yet.
 
    	}
 
    	if(checkDB != null){
 
    		checkDB.close();
 
    	}
      	return checkDB != null ? true : false;
    }
}